Fuzzy logic is an uncertainty management system which is premised on the idea that items may partially be members of some sets (fuzzy sets). While the fuzzy calculus can be applied to many analytical procedures (like fuzzy clustering or fuzzy regression), in practice, fuzzy logic most often is applied as a set of fuzzy rules, such as: if Speed is Too_Fast then Apply_Brakes if Speed is Way_Too_Fast then Stomp_On_Brakes etc. ...where conditions and antecedents are defined in mathematical terms. An introductory article on fuzzy logic I published a few years ago is available at: Putting Fuzzy Logic To Work (PC AI Mar/Apr 2002)